Insulation piercing terminal



Feb. 10, 1959 R. F. DRUM ET AL INSULATION PIERC ING TERMINAL Filed Dec.31, 1954 I 2,873,434 INSULATION PIERCING TERMINAL Raymond F. Drum,Choconut, Pa., and Leslie A. Weun,

Binghamton, N. Y., assignors to International Business I MachinesCorporation, New York, N. Y., a corporation of New York ApplicationDecember 31, 1954, Serial No. 479,117

2 Claims. (Cl. 339-97 This invention relates to terminal elements forelectrical conductors and more particularly to an improved terminalelement construction and to an improved method of securing terminalelements to insulated electrical conductors.

The fabrication of complicated electrical circuits into component unitshas been greatly facilitated by the use of terminal elements securableto the ends of insulated electrical conductors. Recent years have seenan increase in use of terminal elements particularly of the type whereinthe insulation covering a conductor is pierced by suitable points formedintegral with the terminal element as the same is deformed intoengagement with the conductor. Such piercing type of terminal element,although providing for ease of assembly and consequent decrease offabrication expense, requires the utilization of special dies forforming the same and oftentimes results in a terminal element connectionthat fails to provide the desired extent of electrical contact area andmechanical strength in the assembled unit.

This invention may be briefly described as. an improved terminal elementconstruction and method for securing terminal elements to insulatedelectrical conductors wherein insertion of the insulated conductor intothe terminal element results in a partial, though extensive, strippingof the insulation therefrom for increased area of electrical contact,and subsequent deformation of the terminal element results in a joint ofimproved electrical and mechanical properties and characteristics.

The object of this invention is the provision of an improved terminalelement construction for insulated electrical conductors and a methodfor obtaining the same.

Other objects and advantages of the invention will be pointed out in thefollowing disclosure and claims and will be illustrated in theaccompanying drawings which describe, by way of example, the principlesof the invention and the presently preferred embodiments of the terminalelement construction incorporating those principles.

Referring to the drawings:

Fig. 1 is a plan view of a blank for the terminal element preparatory tothe forming thereof;

Fig. 2 is a plan view of the blank of Fig. 1 after it has beenpreliminarily formed to receive an insulated conductor;

Fig. 3 is an end elevation of the terminal'illustrated in Fig. 2; and

Fig. 4 is a sectional view of the terminal after it has been deformedinto engagement with and around an insulation covered electricalconductor.

Referring to the drawings and particularly to Fig. 1, there is provideda terminal blank having a connector portion generally designated 11 anda conductor engaging portion generally designated 12. The connectorportion 11 after deformation thereof is adapted to be soldered orotherwise connected to a terminal strip or like article and thereforemay have any desired configuration in accordance with the dictates ofthe ultimate connection to be effected. The conductor-engaging portion12 is provided with a peripheral wing portion 13 and a secondary wing2,87 3,434 Patented Feb. to, 1959 Ice 2 portion disposed within saidindicated at 14.

Figs. 2 and 3 illustrate the requisite preliminary shaping of the blankinto a configuration adapted to receive the peripheral wing portion asinsulated conductorspreparatory to the actual mounting of the terminalthereon. As there illustrated, the peripheral wing portions 13 are bentsubstantially into a U shape as illustrated at 15, and the secondarywing portions 14 are bent substantiallyinto a U shape of appreciablyshorter radius than that of the peripheral wing portions as bestillustrated 'at16. Because of the shorter radius of curvature of thesecondary wing portions 14, both of the ends thereof 17 extend somewhatabovethe corresponding opening 18in the peripheral wing portion 13 fromwhich they were blanked and provide a relatively sharp, inwardlydisposed edge 19*asa r'esult of the degree of bend to which they weresubjected.

The preformed terminaleleinent as illustrated in Figs. 2 and 3 isattached to the end of an insulated conductor by first inserting the end"portion at the conductor downwardly into the substantially U-shapedportion of the terminal element defined by. the deformed secondary wingportions 14. The spacing intermediate the arms of the substantiallyU-shaped portion defined by the secondary wing portions 14 should besuch as to effect a removal of the side portions of the insulatedcovering on the conductor as the same is moved downwardly past the edge19 of the end portions 17 thereof. The stripping of the side portions ofthe insulation from the conductor results in the exposing of arelatively large area of the conducting material, which area, uponfurther depression into the unit, is then disposed immediately adjacentto and in intimate contact with the arms of the U-shaped secondary wingportions 14.

After insertion of the conductor with the consequent removal of the sideportions of the insulation therefrom as described above, the arms 17 ofthe secondary wing portions 14 are bent around the wire as illustratedat 20 in Fig.4. Simultaneously therewith the peripheral wing portions 13are clamped around the secondary wing portions so that its sides overlapthe latter as illustrated at 21 in Fig. 4.

Due to the requisite and necessary removal of the side portions of theinsulation on the insulated conductor effected during insertion of theconductor into the unit, the spacing of the arms 17 of the secondarywing portions 14 is somewhat critical and must necessarily vary. inaccordance with the size of the insulated conductor being utilized. Thefollowing dimensions relating to the capital letters on the drawingshave been found in practice to be satisfactory in effecting the desiredremoval of the s ide portions of the insulation on the conductors: for#20 wire size for a terminal constructed in accordance with theprinciples of this invention: A-.025 inch; B-.1l0 inch; C.020 inch;D-.235 inch; and E.040 inch.

The advantages obtainable through the above terminal construction andmethod of forming the same are a re sultant terminal having greaterelectrical contact area, greater mechanical strength, and theelimination of dies of special configuration as conventionally requiredfor the present-day piercing type of terminal construction.

The principles of the invention have been described and illustrated in asingle operative unit for the purpose of teaching those skilled in theart how the invention may be performed. Certain changes in configurationwill appear to those skilled in the art, and it is contemplated thatsuch changes may be employed but yet fall within the spirit and scope ofthe invention insofar as they are within the claims that are to follow.

Having thus described our invention we claim:

1. A solderless terminal for insulated electrical conductors comprisinga plurality of integral conductoramass-4 3 r pp n p i n a f rela ely.risis e deforma substantially U-shaped cross section with'common baseportions; one of said portions having parallel conductorgripping arms ofsubstantially shorter-longitudinal and arm lengths than, and beingsymmetrically positioned within, the, arms of the other portion andbeing provided with elongated relatively blunt parallel ends spaced by a,value substantially equal to theconductor transverse dimension to stripsections of the insulation from and bare the side portions of aninsulation covered electrical conductor forceably inserted between thearms of said one portion; and said arms -o f said other portion beingspaced by the insulated conductor transverse dimension'to guide aninsulated conductor symmetrically into said one pair of arms during saidinsertion thereof,

A c ps d r es te m na s ferv susla ec CQnducor -c p a n tar condu t v-memberh y gn s f b a all ,U \-S P s .zq osssec ena po ions. "p 70-viding ir o aims nen r. of aid. arm ingra a and relativelyrigidandipositioned to, be upstanding in y t ca re a ons ithin -.an .thp i ofv s i fir but having shorter arrn and longitudinal lengths:thannsaid' other pair of said arms and havingrelativelytbluntarmcompassing engagement thereof with theinsulationstripped areas of said conductor and crimped overlyingencompassing engagement of said other pair of arms with at least thecrimped ends of said one pair of arms and with longitudinal sections ofthe insulated conductor located on each side of said one pair of arms;

References Cited in the file of this patent UNITED STATES PATENTS1,608,578 Buckenberg p Nov. 30,1926 2,501,187 Oortgijsen Mar. 21 19502,501,870 Malhoit Mar. gs, 1 950 2,518,489 Orlando Aug. '15, 19502,680,235 Pierce Junel, 1954

